Listed below are the 45 openly out athletes participating in the Rio 2016 Summer Games – they represent 21 sports and come from 13 countries. While this is the largest number of out Olympians to date, the really big news for the Rio 2016 Summer Games may well be the future participation rules for intersex athletes and what it may or may not do for transgender athletes.

Over the last five or six years, some transgender athletes like Fallon Fox (MTF) and Chris Mosier (FTM) have been more public about their transitions. For sports governing authorities there have been legitimate questions about potential advantage over an opponent due to changing hormones levels, especially males who have transitioned to female. Fortunately, medical research has shown that female athletes who were born male do not have a hormonal advantage over women who are born female since with hormone replacement therapy (HRT), trans women’s physical strength diminishes and both muscle mass and bone density decrease.

But now the spotlight has shifted to intersex athletes. “Intersex,” according to the human rights arm of the United Nations is the preferred umbrella term for people born with sex characteristics “that do not fit typical binary notions of male or female bodies.” It is being used to replace the heavily stigmatized term, “hermaphrodite.”

Caster Semenya, a South African runner is one of the best known examples of the confusion that is circling around acceptable testosterone limits for female athletes that for the Rio Games at least, are in limbo. While Semenya has never said she is intersex, over the years she’s been required to take a number of “invasive and embarrassing gender tests” due to her heavily muscled body and impressive speed.

In a fascinating and well-written article by Scott Gleeson and Erik Brady for USA Today Sports, they say, “Track observers believe Semenya is hyperandrogenous, meaning her body naturally produces high amounts of testosterone, the hormone that helps build muscle, endurance and speed. The International Association of Athletics Federation (IAAF), track and field’s governing body, has rules limiting the amount of naturally occurring functional testosterone allowed for female athletes. But today those limits are in limbo.

“The Court of Arbitration for Sport (CAS) suspended them last summer, citing insufficient evidence that high levels give female athletes a boost in performance. The IAAF has until next summer to make a case for its regulations or the court will abolish them. The Rio Games, meantime, fall during an interregnum where the rules don’t apply.”

All this begs the question of whether or not the outcome of what hormonal limits will be accepted for intersex athletes will be unfair to female transgender athletes. Stay tuned – don’t expect that it will all be figured out by the time the Rio Games are over.

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